DSE, the things you mention are not reliability issues, and ANY car would give you duff BHP figures if taken to the wrong rolling road.
A throttle adjustment any car would need.
So I wouldn’t get dishearted with the car just bec ause of that.
Now, the throttle: have a friend press on the throttle pedal fully and you go to the engine side, see where the cable ends and see what the cable is rotating.
If when he has applied full throttle you can still move the turning thingie with your thumbs, the throttle is not opening fully. Adjust the nuts on the threaded metal cable end until you do.
Dave explained the 90 de BTDC and how to check the cam timing, but if it’s too daunting give it to a dealer who can do that. It should take about 30 min to check to someone that has done it already, but close to 4 hours if you have no idea.
And the Dynojet RR, I know the name from motorcycles, but hadn’t heard it on the car world. How far is Emeralds from you? could it be worth a visit when you have checked the timing, throttle and cleaned your filter?
But these cars do require some fiddling all over the place, it’s just part of the fun IMHO. It’s like owning a race car, needs constant fiddling all over
Thanks everyone. I will do the throttle check tonight, god I hope its that !! I am going to live with it for this trackday (I will just have to drive harder !!), I will then book her into christopher neil or someone else. Any suggestions in the manchester area, or should I make the pilgrimage to emeralds ?
But these cars do require some fiddling all over the place, it’s just part of the fun IMHO. It’s like owning a race car, needs constant fiddling all over
The thing is that with a normal car you’re not really interested in top performance so some may get lost in some adjustments.
If you did, you would find that any car needs to be adjusted here and there.
Heck, was the same with bikes, nobody complained about things until they wanted more and more.
But I have to say that some cars come better assembled from factory, and Exiges are known for having these kind of details badly done. Maybe the cable stretches with time?
Don’t know, but once you adjust it, I have seen it doesn’t need adjusting again.
But these cars do require some fiddling all over the place, it’s just part of the fun IMHO. It’s like owning a race car, needs constant fiddling all over
The thing is that with a normal car you’re not really interested in top performance so some may get lost in some adjustments.
If you did, you would find that any car needs to be adjusted here and there.
Heck, was the same with bikes, nobody complained about things until they wanted more and more.
But I have to say that some cars come better assembled from factory, and Exiges are known for having these kind of details badly done. Maybe the cable stretches with time?
Don’t know, but once you adjust it, I have seen it doesn’t need adjusting again.
True to a point, but I think it’s more a case of Q.C.
Look at the “same” bolts missing from our exiges eh?
As Uldis says, I would really call this a reliability problem. I enjoy tweaking and checking things occasionally. That’s part of what separates proper sports cars from run of the mill production cars.
The throttle problem usually comes from the poor assembly at the pedal mechanism. First check that the pivot is not coming loose.
When you adjust the cable at the engine end, you’re just effectively shortening the cable which can interfere with with engine idle. You should adjust this almost to the point where it prevents the throttle from reaching it’s idle position. You should now have next to no slop in the pedal travel. Next, check for full throttle opening again. If the throttle still doesn’t open fully, you need to adjust the bolt behind the pedal which acts as a stop.
Incidentally, you shouldn’t actually get full 100% opening of the throttle because you will be stretching the cable. Try to aim for a tiny loss of throttle movement. The last couple of percent don’t really cost any significant power.
But I beg to differ on the full throttle thing, you can get 100%, what you can’t is get full stretch.
See, the throttles will open 100% before the cable stretches, just because of the angle and the fact that it’s a bit stiff.
Check it, there’s a point where the throttle is fully open and you can still push a bit on the cable.
If you go beyound this point, before getting to the danger zone (pulling on the cable) when the cable stretch/non (with temperature) will turn the butterflies a bit on idle, so you would notice the car idling high…
That is, if the begining position is also adjusted properly.
I have checked the throttle cable and with the pedal to the metal I can still turn the wheel thing (sorry ) about another 3-4 mm. is this normal or should I dial this out with the bolts at the engine end ? If I should adjust this out, how much travel should there be with the spinny thing (sorry )?
Well I seem to remember reading advice on adjusting the throttle from a pretty reliable source (maybe Dave Andrews, or somebody at Lotus). I think they suggested a small amount of slack to avoid stretching the cable, but maybe I’m talking out of my bottom (again).
I would definately suggest that 3-4 mm is too much. Personally, I’d be looking for less than 1mm, but I’m sure you can go with Uldis’ technique. Just make sure there’s not a massive amount of tension in the cable.
well I have done it, there is now around 1 mm of slack at full throttle (everything cold). Should I remove this as well, the cable isnt too taught ? The throttle pedal has absolutely no ‘dead’ travel in it, and the car does feel sharper (or is it wishful thinking ?). Well at least the pedal feel/response is much better.
As power for the VHPD is roughtly linear, if you take 3-4mm as a percentage of the whole travel and add that percentage to your bhp output you may get close to what your engine is really worth!
A power upgrade you don’t even have to tell the insurance company about!
Right I have just removed the last 1 mm, I reckon the wheel turns around 3 or 4 cm, that means I have just gained around 10% hp or about 17 hp. well fook me, that makes my car around 185 hp which sounds much much better to me (I am starting to believe its a 177 car not 190 as I was sold by Barry Ely in London).
DSE - wouldn’t you have expected the rolling road operator to have checked the throttle opening when the car apparently was underperforming by so much? Are they actually skilled mechanics or donkeys with a plug & play machine?
The power curve may be linear, but that doesn’t mean that the engines response to throttle position is also linear, the two are not connected.
Since the 1800K has been shown to produce over 240BHP on 42mm TBs and the VHPD ones are 45mm it follows that the TBs are oversized for the application. It is not unknown for engines to give more power on slightly less than full throttle if the overall throttle area is too large. I would think that at 90% full throttle you wont be far off maximum power, certainly the TBs will flow enough air since the change in butterfly protrusion into the airstream is less per degreee of rotation as the throttle plate axis approaches the airflow direction, in this respect it is anything but linear in response. The main difference might be in drag across the plate.
Dave - I think I recall reading something from Dave Walker that he was amazed at how much difference this issue made - something to do with the butterflies -
In other words he thought it would not make much difference but it did - was in a CCC issue or something